1. Field of the Invention
The present invention relates to a filtration device for the separation of blood plasma used to separate blood plasma from whole blood, and more particularly, to a disposable multi-layered filtration device for the separation of blood plasma which can be applied to a biochip.
The present invention was supported by the IT R&D Program of MIC/IITA [2006-S-007-02, Ubiquitous Health Management Module/System].
2. Description of the Related Art
Blood circulates around the body through blood vessels of a person or an animal. The blood has various functions of supplying oxygen inhaled via lungs to tissues, carrying carbon dioxide from the tissues to the lungs to be exhaled, supplying nutrients absorbed by the digestive organs to other organs or the tissues, transporting a waste product of metabolism produced by cells to the kidney so that the kidney secretes the waste product into the urine, transporting hormones produced by the endocrine glands to corresponding organs and tissues, transporting heat through the body to regulate the body temperature, attacking and detoxifying infections agents and foreign substances, and the like.
Blood is used as an important indicator for diagnosing diseases or health states. Particularly, a protein chip is a kind of biochip for detecting or measuring an expression of a specific protein or an amount of a specific protein in a blood sample to diagnose diseases associated with the protein and manages convalescence.
Blood is composed of a liquid called blood plasma and blood cells suspended within the plasma. The blood plasma is predominantly water containing dissolved proteins, glucoses, fatty acids, minerals, and other substances, and the blood cells present in blood are red blood cells, white blood cells, and platelets. Since the protein to be detected generally presents in blood plasma, a protein chip needs a filter element for separating only blood plasma from blood in order to obtain quantitative results with high sensitivity.
A general blood filter is used to process rapidly a large amount of blood. However, a blood filter of the protein chip requires fast separation using a small amount of blood without contamination of blood plasma.
As existing methods introduced to separate blood plasma from whole blood, there are a method of separating blood cells and blood plasma from each other by using centrifugal force, a method of disposing a microstructure having a size smaller than blood cells at a flowpath and pumping blood so that blood cells are filtered out and only blood plasma is remained, a method of disposing a diaphragm having a small height so as not to enable blood cells to pass through but to enable blood plasma to pass through the diaphragm, a method of disposing a paper, a glass fiber, a porous medium, or a membrane at a side or front surface of flows of blood to separate blood cells, a method of using sedimentation effects of blood cells caused by gravity so that blood cells and blood plasma are layered so that the blood plasma can be extracted, a method of applying an electrical signal to deflect flows of blood cells, and the like.
Specifically, as an example, PCT International Publication No. WO2004/084974 (titled “BLOOD FILTER DEVICE AND METHOD OF PRODUCING THE SAME”, published on Oct. 7, 2004) discloses a blood filter device which has a flow inlet formed at a side surface of a dome portion horizontally so that blood flowing through the flow inlet into the dome portion passes through a filter and flows out through an outlet and impurities, thrombus, and the like in the blood are removed to remain only blood plasma. Here, air bubbles in the blood can be easily removed through an air outlet provided in the top of the dome portion.
As another example, PCT International Publication No. WO2004/046716 (titled “PLASMA OR SERUM SEPARATION MEMBRANE AND FILTER APPARATUS INCLUDING THE PLASMA OR SERUM SEPARATION MEMBRANE”, published on Jun. 3, 2004) discloses a filter apparatus which has a tube-shaped member including a filter member provided at the top portion of the tube-shaped member. After the tube-shaped member is sealed and fixed, the tube-shaped member is decompressed so that blood collected in the tube-shaped member is filtered to separate blood plasma or serum.
As another example, PCT International Publication No. WO99/058172 (titled “FILTER DEVICE AND METHOD FOR PROCESSING BLOOD”, published on Nov. 18, 1999) discloses a filter device for processing blood to effectively remove specific components from a large amount of blood. In the filter device, a blood filter layer and a space layer on a sheet where blood flows more easily through the spacer layer than through the filter layer are stacked and coiled, and an end portion of the spacer layer on the sheet is exposed to an outer circumference of a filter member, so that several liters of blood are processed and desired target materials can be easily removed.
However, most of the existing blood filters are used to process a large amount of blood and cannot be implemented as chips.
In addition, existing blood filter devices have structures including filter members such as papers, glass fibers, membranes, porous media, and the like, so that manufacturing processes are complex and high manufacturing costs are required, and the filter devices are not appropriate for disposable uses.
In addition, the existing blood filter devices have problems such as blocked flow paths, decreases in blood plasma separation efficiency, increases in separation time, and complex operations, and the like, due to structural characteristics.